Electrical switches and devices employing electrical switches



June 10, 1969 T. Q TAYLQR;

ELECTRICAL SWITCHES AND DEVICES EMPLOYING ELECTRICAL SWITCHES SheetFiled Feb. 15. 1967 O0 0 O O0 0 O o O O O D o o AH O O k\ 00 o o o oJune 10, 1969 'r. c. TAYLOR 3 ELECTRICAL SWITCHES AND DEVICES EMPLOYINGELECTRICAL SWITCHES She et Z 01" 2 Filed Feb. 15. 1967 zg 22 1 2/aUnited States Patent 3,449,533 ELECTRICAL SWITCHES AND DEVICES EMPLOY-ING ELECTRICAL SWITCHES Thomas Charles Taylor, Farlington, England,assignor to Sealectro Limited, Farlington, England, a British companyFiled Feb. 15, 1967, Ser. No. 616,252 Claims priority, application GreatBritain, Feb. 16, 1966,

6,862/66 Int. (:1. H01h 43/08, 3/00, 9/00 US. Cl. 20046 4 ClaimsABSTRACT OF THE DISCLOSURE This invention relates to electrical switchesand to devices employing electrical switches, for example, devices forsensing the holes in punched cards or webs (herein called cards).

According to the invention an electrical switch comprises a flexibleblade which is anchored at one end, the blade having or providing amovable contact member intermediate in the length of the blade, a stopwhich engages one side of the blade and which is located between thesaid movable contact member and the other end of the blade, and a fixedcontact member located opposite the said movable contact member forengagement thereby, the stop member being so arranged that transversemovement of the said other end of the blade flexes the blade about thestop as a fulcrum and moves the movable contact member into and out ofengagement with the fixed contact member.

In one form of the invention the blade is resiliently biassed to holdthe movable contact member in engagement with the fixed contact memberand the stop is located on the same side of the blade as the fixedcontact member whereby movement of the said other end of the blade toflex the blade about the stop causes the movable contact member to moveaway from the fixed contact member and hence to open the contact membersof the switch.

In another form of the invention the blade is resiliently biassed tohold the movable contact member separated from the fixed contact memberand the stop is located on the opposite side of the blade from the fixedcontact member whereby movement of the said other end of the blade toflex the blade about the stop causes the movable contact member to moveinto engagement with the fixed contact member and hence to close thecontact members of the switch.

The invention also includes a device for sensing the holes in punchedcards comprising a support for a card to be sensed, a switch as claimedin any one of claims 1 to 3 for each station to be sensed, the blades ofthe switches being generally substantially perpendicular to a card onthe card support with the said other ends of the blades positioned tocontact the card and sense the holes, and means for moving the saidother ends to flex the blades about the stops whereby said other endshave components of movement parallel to the card and also towards andaway from the card and return movements of blades which do not senseholes will be restricted by engagement with the card.

Preferably the card support is vertical and the blades are substantiallyhorizontal.

It is also preferred that the blades are arranged in parallel rows, themeans for flexing the said other ends of the blades in one or more rowsbeing coupled for operation in unison. In this case, the card support ispreferably arranged to move in unison with the means for flexing thesaid other ends of the blades.

By way of example a specific construction of electrical switch and of acard sensing device incorporating the switch in accordance with theinvention will now be described with reference to the accompanyingdrawings in which:

FIGURE 1 is a view of the switch, movable and fixed contact members ofthe switch being held in a moulding of insulating material;

FIGURE 2 is a perspective view of the card sensing device;

FIGURE 3 is a section through the device shown in FIGURE 2, whichsection shows two sensing pins only, one of which is in engagement withan associated fixed contact and the other of which is out of engagement,each pin and its associated fixed contact providing the movable andfixed contact members of the switch shown in FIG- URE 1;

FIGURE 4 is an enlarged view of the movable ends of two of the sensingpins of the device shown in FIGURES 2 and 3, one of which pins hassensed a hole in a card; and

FIGURE 5 is a view of a modified construction of switch.

The subject of this example (especially FIGURES 1 to 4) comprises anelectrical switch having movable and fixed contact members and a cardsensing device employing a plurality of the switches, the movablecontact members of the switches being used as the sensing pins of thesensing device. The following description will thus describe the switchas part of the sensing device but it is to be appreciated that theinvention includes the construction of the switch per se. For example,the switch may be used as part of a jack plug in a plug board.

With reference to FIGURES l to 4, a card 9 to be sensed has 960 separatepositions in which a hole may be punched. The card sensing device isthus provided with 960 sensing pins 10 arranged in 12 parallel rows 11arranged one on top of each other. The device is also provided with aslot 13 with a card support 14 on the remote side of the slot from thepins 10. The card support is made up from a moulding made of, e.g.material marketed under the trademark Bakelite, the moulding havingrecesses 15 aligned with each row of pins.

Each pin 10 is formed from a length of beryllium copper strip or, as inthis example, of wire which has first been flattened at 16 into stripform to form a blade portion having increased flexibility. The flattenedsection 16 of each pin is inserted into a recess in a moulding 17, madeof insulating material, the ends 18, 19 of the pin projecting from theends of the moulding. The pin is also held at a point 20 adjacent itsend 18 and one surface of the pin adjacent its other end 19 engages at apoint 22 a surface or stop member 21 forming part of the moulding. Thedesign of the moulding is such that the end 19 of the pin may be flexedor moved in a direction tending to pivot the end of the pin about thepoint 22, i.e. in the direction of arrow A, the point 22 thereby actingas a fulcrum. Such movement of the end 19 of the pin will cause adeflection of the centre or flattened section 16 in the oppositedirection. With regard to FIGURE 1, the movable end 19 of the pin isshown in its relaxed position, which '3 position is defined by anabutment 23 forming part of the moulding 17.

Each moulding 17 also houses a contact 24 which is formed from similarwire to that of the above-described pin 10. One end 25- of the contactprojects from the moulding adjacent the end 18 of the pin and thecontact is held in the moulding at a point 27 in a similar manner tothat in which the pin is fixed at point 20. The other end 28 of thecontact is, in this example, flattened and the design of the moulding issuch that the contact engages, at point 29, the centre section 16 of thepin, when the pin is in its relaxed position. The end 28 of the contactis also split in two by a lengthwise slit adjacent point 29 to providetwo contact surfaces between the contact and the pin. The ends 18, 25 ofthe pin and contact respectively act as contacts-for an electricalcircuit. Also, in the case.of the present example, the end 19 of the pinis capable of sensing a hole in the card to be sensed.

For each row of pins, a suitably insulated tie-bar 30 (see FIGURES 3 and4) is provided and a mechanism is provided for moving the tie-barssimultaneously first in the direction constituted by FIGURE A (seeFIGURE 1) and then in the opposite direction. The tie-bars 30 arethereby capable of flexing the pins by moving the movable ends 19 of thepins in the direction of arrow A (see FIGURE 1) and then allowing theends and hence the pins to return at least a part way towards theirrelaxed positions when the bars are moved in the opposite direction. Asshown in FIGURE 4, each pin that senses a hole 31 in the card 9 willreturn to its relaxed position and each pin that does not sense a holeis retained partly flexed by the card itself. Also, as described above,it is only when the pin moves to its fully relaxed position that the pinwill engage its associated contact and hence complete the electricalcircuit, of which the pin and the contact form a part.

The current in each electric circuit will normally be about 1 amp. and alocking mechanism is thus provided to prevent the electric circuitsbeing completed when a card is not being sensed, since with no card 9 inthe slot 13 each pin is in its relaxed position and hence engages itsassociated contact. This locking mechanism comprises a movable arm orswitch at the base of the slot 13 which is tripped by the forward end ofthe card when it is in its position for the holes therein to be sensed.

The mechanism provided for moving the tie-bars 30 to move the movableends 19 of the pins comprises a cranked lever 32, pivotally mounted tothe casing of the device such that the arm 33 of the lever can be movedby the operator to eifect movement of the other arm 34 and hence upwardmovement (as viewed in FIGURE 3) of both the card support 14 and each ofthe tie-bars 30. Such movement of the tie-bars will move the movableends of the pins, the pins thereby allowing a card to be inserted intothe slot 13. The return movement of the arm 33 of the lever 32 iseffected, or at least assisted, by a spring 35 and the return movementof the card support and the tiebars is effected by a spring 36. Safetymeans to prevent the insertion of a card without operation of the arm 33of the lever 32 is either provided by the size of the knob 37 on the endof the arm 33 blocking the entrance to the slot or, as shown in FIGURE3, by an additional plate 41 fixed to the arm 33, which plate covers theslot when the arm is in its inoperative position, i.e. its positionshown in FIGURE 3. The arm may, if desired, be solenoid-operated, inwhich case a pair of buttons would be provided for moving the cardsupport and the tie-bars.

Further safety means is also provided so that the card can only beinserted into the slot in one predetermined manner. These further safetymeans comprise a springloaded detent tor co-operation with a chamfer onone of the corners of the card. The sensing device is also provided witha light to show when a card is being sensed and there may be a furtherlight which can be caused to operate when a card is not being sensed.

In operation of the sensing device, the arm 33 or the lever 32 isrotated in a clockwise direction (as viewed in FIGURE 3) to cause thetie-bars 30 to effect anticlockwise rotation of the movable ends 19 ofthe pins and to move the said ends of the pins. A card is then insertedbetween the ends 19 of the pins and the card support 14, which cardtrips the aforesaid locking mechanism of the sensing device. The arm 33of the lever 32 is then allowed to return to its original position by orassisted by the spring 35. Hence the ends 19 of the pins move towardstheir original positions and the pins that sense a hole in the card willreach their original positions and these pins will hence make electricalconnection with their associated contacts. The arm 33 of the lever 32 isthen again rotated in a clockwise direction to allow the card to beremoved. The removal of the card may be partially assisted by a crankedlever 42 located in the base of the slot 13 to expel the card into aposition in which it can be gripped by the operator.

The invention is not restricted by the specific details of the devicedescribed above. For example, during assembly of the sensing devicedescribed above, it may be necessary to use shims to counteract anydiscrepancies in the sizes of the mouldings which may arise duringmanufacture thereof.

Also, the longintudinal axes of the pins 10 of the sensing device asdescribed above lie in horizontal planes and the card to be sensed isinserted into a vertical slot 13. The device could, of course, be usedin a position in which the longitudinal axes of the pins lie in verticalplanes. In this case the slot 13 would be horizontal and the pins couldbe arranged either above or below the slot.

Furthermore, the switch described above has a pin 10 which, in itsrelaxed position, makes contact with the fixed contact 24 at point 29.However, in a modified construction (see FIGURE 5), the switch may beconstructed, perhaps for use other than in a card sensing device, sothat the flattened section 16 of the pin 10, when in its relaxedposition, is out of engagement with the fixed contact 24. In thismodified construction, a stop member 21a having the fulcrum point 22 islocated adjacent the other surface of the section 16 of the pin 10. Theposition of the abutment 23 is also reversed so that the end 19 of thepin still passes between the stop member 21a and the abutment 23. Thus,in operation, when the free end 19 of the pin is flexed in the directionof arrow B, the pin will act against the surface of the stop member 21aand will deflect the flattened section 16 of the pin into engagementwith the end 28 of the fixed contact 24 thereby closing the contactmembers of the switch.

I claim:

1. A device for sensing the holes in punched cards comprising a supportfor a card to be sensed, a switch for each station to be sensed, saidswitches each including a flexible blade having anchoring means at oneend, a movable contact area inter-mediate the length of the blade, and afree end offset from the blade line for making contact with the card, astop which engages one side of the blade and which is located betweenthe movable contact area and the free end, and :a fixed contact memberpositoned adjacent to said contact area for engagement therewith, theblades of the switches being substantially perpendicular to a card onthe card support with said free ends positioned to contact the card andsense the holes, and means for moving said free ends to flex the bladesabout the stops whereby said free ends have components of movementparallel to the card and also perpendicular to the card and wherebyreturn movements of the blades which do not sense holes will berestricted by engagement with the card.

2. A device as claimed in claim 1 in which the card support is verticaland the blades are substantially horizontal.

3. A device as claimed in claim 1 in which the blades .5 6 are arrangedin parallel rows, the means for flexing the 2,842,632 7/1958 Edwards.said free ends of the blades in each row being coupled 3,144,524 8/1964Hawley et al. for operation in unison. 3,177,311 4/ 1965 Torrico 200474. A device as claimed in claim 3 in which the card 3,221,131 11/1965Bury.

support is arranged to move in unison with the means for flexing thesaid free ends of the blades. 5 RO E SCHAEFFER, Primary Examiner.

References Cited D. SMITH, JR., Asszstant Exammer.

UNITED STATES PATENTS U.S. Cl. X.R.

2,567,552 9/1951 Cronin. 10 200-166; 235-6111

